Adding support for new columns in logging database

I've added a new column to the CategoryLog table and need to create a custom trace listener that inserts the value. Finding it difficult to track down step-by-step documentation on how to do this.
Am I missing something or did I simply code this incorrectly? I've been unable to get this to work.

(1) Created a class faLogEntry that inherits from LogEntry and added in the new column

(5) Add CustomTraceListener to app.config. In the "type" property, select the assembly that contains the faCustomTraceListener class I created in step 2. This is where I receive an error: 'no type found in assembly that inherits from CustomTraceListener'.
I've tried changing the class I'm inheriting from FormattedDatabaseTraceListener to CustomTraceListener and get the same message.

You mean in step #5? You simply need to close and re-open Microsoft Visual Studio. What happens is that the current domain has already loaded the assembly of the custom database trace listener which initially inherits from the FormattedDatabaseTraceListener.
Even after changing it to CustomTraceListener, when you try to load the assembly in the type picker, it doesn't update the previous assembly and so it still see your custom trace listener inheriting from FormattedDatabaseTraceListener.

On a different note, the entire steps isn't quite correct. First, as you have already noticed, it should inherit from CustomTraceListener. Next is, the ConfigurationElementType specifying FormattedDatabaseTraceListenerData will cause it to still
create a FormattedDatabsaeTraceListener rather than your custom trace listener. Since this looks like the steps wants to have full integration with the configuration tool, you should create a new class inheriting from TraceListenerData and use that class
as the type you specify in the ConfigurationElementType attribute. If you're using version 4.1 and lower , you also need to create a corresponding assembler class. You can refer to the source code to get an idea. In EntLib 5.0, assembler
classes are no longer needed and writing custom providers is much easier. This is documented, you can check it out
here.

Thanks for your reply. I am now one step further. The custom trace listener works fine now I am stuck to integrate it with configuration tool. Configuration tool does not recognize this new custom trace listener. When I try to open configuration file with
configuration tool I get exception “Invalid TraceListenerData type in the configuration listenerData Type …….”. Am I doing sth. wrong or configuration tool does not support this new type?

By the way I am using version 4.1. I did following so far:

//Create a new trace listener by inheriting from FormattedDatabaseTraceListener

What you're trying to do is a basic integration right? If yes, then as what Sarah said, your Custom TraceListener should inherit from the
CustomTraceListener class and the ConfigurationElementType should be of type
CustomTraceListenerData. Therefore your Custom Trace Listener may look something like this;